The present invention relates to antenna systems for creation of highly shaped beams of irregular outline.
Communications satellites in geosynchronous orbit are employed to allow communication from one earth station to another. Such satellites typically employ antenna systems engineered for coverage of specific land masses so as not to waste antenna gain over unpopulated areas. Antenna systems for providing highly contoured antenna patterns are, therefore, required to enhance the efficiency of the communication system.
Heretofore, a cluster of waveguide horns feeding a parabolic reflector was the only satellite antenna that produced highly contoured beams. This type of system suffers the disadvantages of high cost, thermal distortion and considerable volume requirements.
Modular phased array antenna systems have long been utilized in radar applications, typically as an element in a radar system to sweep a narrow beam of RF energy past a target and thereby obtain an imaging of the target from the reflected signals. Insofar as is known to applicants, phased array techniques have not been used before for space antenna subsystems because of the relatively high costs associated with standard treatment of their design, and the fact that such standard treatments were not believed to lead to practical configurations for satellite and space configurations.
It is, therefore, one object of the invention to provide a modular phased array antenna system for creating a highly contoured beam pattern.
Another object of the invention is to provide a direct radiating antenna which can create a highly configurable pattern.
Yet another object of the invention is to provide a modular contoured beam phased array which is relatively small, compact, light and less costly than prior art systems.